Anticonvulsant Drug Blood Levels: Practical Applications Based on 12 Years’ Experience

WITHIN recent years, sophisticated techniques for measuring anticonvulsant drug serum levels have been developed. 1 The use of such procedures constitutes a major advancement in the medical management of the patient with epilepsy. The purposes of this report are to present (1) data relative to the therapeutic and toxic blood level ranges of phenobarbital and diphenylhydantoin (Dilantin), and (2) the significant and practical indications for determination of anticonvulsant-drug levels in the blood. Determinations of Drug Levels in the Blood Clinical response remains the most important criterion in regulating the dosage of antiepileptic medication. However, we have found drug blood level determinations to be helpful in the management of some patients, particularly those who do not respond to average or maximal doses or who manifest signs or symptoms of toxicity while receiving small or conventional dosages of anticonvulsant agents. We have performed thousands of serial diphenylhydantoin and phenobarbital blood level determinations